For cosmetic purposes, colored contact lenses having one or more colorants dispersed in the lens or printed on the lens are in high demand. These colored contact lenses enhance the natural beauty of the eye, or provide unique patterns on the iris of the wearer, or provide non cosmetic patterns.
In general, there are two types of colored contact lenses. The first are contact lenses which use essentially transparent enhancement colors that allow the color of the natural iris to show through but combine with that natural color to produce a new appearance. Such tinted lenses are typically used to turn a light eye (e.g., green) to a slightly different hue (e.g., aqua). This class of colored lenses may not be able to change an underlying dark colored, brown iris to blue. The second category is the class of opaque colored lenses having a continuous opaque pattern that fully covers the iris or having an intermittent opaque pattern that does not fully cover the iris. Opaque colored contact lenses can effectively and substantially change the wearer's eye color.
Over the years many attempts have been made to enhance or change the color of one's eyes using colored contact lenses with varying degrees of success (see, for example, U.S. Pat. Nos. 4,634,4495; 4,954,132; 414,477,449; 5,793,466; 5,936,705; 6,030,078; 6,132,043; 6,196,683; 6,322,214; 6,494,575; 6,523,953).
Those colored lenses do enhance or change the eye color of the wearer, but they may also have one or more disadvantages as follows. First, they may not achieve the strikingly natural appearance desired in the industry. Second, The opaque colors for changing the eye color of the wearer may yield less effective results for consumers with medium-dark eyes than consumers with dark-eyes, for whom the color modification is more evident. Accordingly, there are still needs for colored contact lenses that can change the hue or color intensity enough to visibly see a difference compared to the natural iris while maintaining the underlying iris structure.